A known bumper reinforcement used for a bumper apparatus for a vehicle is disclosed in JP2006-151095A (hereinafter referred to as Patent reference 1). The known bumper reinforcement disclosed in Patent reference 1 is made of aluminum alloy extruded material and includes a hollow cross-section, and is arranged at a vehicle to extend in a width direction thereof. The known bumper reinforcement includes end portions each of which is bent toward a vehicle body in a bending process. The known bumper reinforcement is mounted on a supporting member at the end portions and is supported by the supporting members. The supporting member may correspond to a side member of the vehicle body or a stay (alternatively, a crush box for absorbing an impact or a shock by crushing may be used) attached to the side member.
The known bumper reinforcement disclosed in Patent reference 1 is made of the aluminum alloy extruded material including the hollow cross section and is arranged at the vehicle to extend in the width direction thereof. The known bumper reinforcement includes a body portion of which end portions are bent toward the vehicle body and a pair of reinforcement members joined to vehicle-exterior-side-end-portions of the body portion. According to the known bumper reinforcement, a diagonally-cut-off portion (that is, the cut-off portion where an amount of cut-off increases gradually toward an end of the vehicle-exterior-side-end-portion) is formed at each vehicle-exterior-side-end-portion at which the bending is applied, and a reinforcement member is joined to each diagonally-cut-off portion. Thus, an inclined surface that matches design of the vehicle is obtained without bending the end portions of the body portion to a great extent. In addition, a strength reduction involved in cutting off the end portions of the body portion is compensated for by the reinforcement members joined to the diagonally-cut-off portion.
According to the known bumper reinforcement disclosed in Patent reference 1, the reinforcement members need to be joined to the diagonally-cut-off portion provided at each end portion of the body portion by means of welding or a mechanical connection, and thus the number of parts and a manufacturing workload increase, which may lead to cost increase. In addition, a shape or configuration of the diagonally-cut-off portion may deteriorate because the reinforcement members are joined to the vehicle-exterior-side-end-portions of the body portion.
A need thus exists for a bumper reinforcement which is not susceptible to the drawback mentioned above.